Now he’s the leader of the Catholic Church, but when he was in preschool, Pope Francis was a devil, according to the school’s head.

Sister Martha Rabino — head of the Colegio de la Misericordia, a Catholic school in Buenos Aires where Pope Francis went to preschool — told People that the pontiff was a bit of a wild child.

“As a boy, he was a little naughty,” Rabino told the mag. “Sister Rose had been his teacher and died at age 101. He was very fond of her. He would always visit her … he would love to ask her, ‘What was I like as a little boy?’ And she would always say, ‘You were a devil!’ and he would laugh and laugh.”

As he grew up, it seems he became a spirited student.

“He used to skip up and down the stairs while learning his two times table,” Rabino told People, “repeating ‘two, four, six, eight’ over and over again!”

Pope Francis is still close with the school, Rabino said.

“All his life he has remained in touch with us,” she said. “He comes spend the afternoon with us twice a year, when he gets all the nuns together and we have tea, and then we take mass.”